The present invention relates to electroacoustic transducers. More particularly, it relates to housing means for electroacoustic transducers.
In the art of medical diagnostics, one form of non-invasive examination of the internal organs of a body under examination involves the use of ultrasonic transducers. These transducers are frequently mounted within a housing filled with an inert liquid and arranged to oscillate in an angularly scanning motion. The housing is generally relatively opaque to the ultrasonic pulses generated by the transducer, with the exception of a relatively transparent window or diaphragm in the operating end of the housing structure. The transducer is positioned and oscillated to direct the acoustic pulses through the diaphragm or window, into the body under examination. The acoustic pulses transmitted into that body are then reflected back toward the transducer at interfaces of tissues within the body, to produce electrical pulses which may be translated into an image of the interior of the body being examined. It has been found, however, that spurious signals have been returned to the transducer as internal reflections from the interior walls of the housing member. These spurious reflections come about because the diaphragm or window is not perfectly transparent to the acoustic pulses and a part of the energy is internally reflected. The spurious reflections will, of course, provide a measure of pulse information which the sensing and translating system cannot differentiate from genuine signals reflected from the interior of the body under examination.